WO2017203085A1

WO2017203085A1 - System for drying liquid blood

Info

Publication number: WO2017203085A1
Application number: PCT/ES2017/070349
Authority: WO
Inventors: José Manuel MAGIDE AMEIJIDE; Hiram VARELA RODRÍGUEZ
Original assignee: Universidade De Santiago De Compostela
Priority date: 2016-05-25
Filing date: 2017-05-24
Publication date: 2017-11-30
Also published as: EP3466507A1; EP3466507B1; ES2597584B2; EP3466507A4; ES2597584A1

Abstract

The invention relates to system for drying liquid blood, which can be used to obtain a dried product from liquid blood and/or derivatives at a low temperature and at a moderate energy cost. The system comprises a set of multi-effect evaporators, a condenser and a heat pump. The liquid blood to be treated is obtained preferably from the meat industry, such as, for example, a slaughterhouse.

Description

LIQUID BLOOD DRYING SYSTEM

TECHNICAL SECTOR OF THE INVENTION

The present invention relates to a system for processing by-products and / or residues of the food industry, more specifically a system for producing a dried product from liquid blood or derivatives.

STATE OF THE TECHNIQUE

It is known by the expert in the processing of liquid blood that the blood produced in the meat sector is usually subjected to treatments that transform it into a blood-derived product, such as the paste of red blood cells, blood plasma, blood serum, blood meal, etc. Sometimes, these transformations generate a product with the appearance of blood, but which technically cannot be called blood.

It should be noted that to obtain a blood derivative, both techniques that extract components from the original blood are contemplated, as well as those that add some component to obtain the derivative. An example of the first case are centrifugal treatments, often used to separate red blood cells. Examples of the type of centrifuges that can be applied for this purpose are those disclosed in US2011 124481 and US4077564. In the second case, the preservation of blood is framed by the addition of anticoagulant salts, such as sodium citrate. There are many techniques that make use of it, for example vacuum evaporation processes in general (within which the present invention fits), add sodium citrate in a step prior to the introduction of blood into the evaporator. The drying of blood or derivatives generates a product of great economic value in the market. It especially highlights its lysine content, an essential amino acid in the diet of many animals. Despite this, its revaluation has traditionally been very complicated. The reason is that two problems arise: the high energy cost of eliminating water from the blood or its derivative, and the need not to raise the temperature of the process of obtaining the product too much. The first problem is that the evaporation of water is very expensive in terms of energy, around 550 Kcal / Kg. On the other hand, the fact of subjecting the blood to high temperatures causes its proteins to denature and lose much of its economic value. So, the smaller the temperature of the treatment, and the shorter it is, the higher the protein quality of the dried product, and therefore the greater the economic value.

Among the techniques for drying a product such as blood, one of the most energy efficient are the multi-effect evaporators, consisting of a series connection of a set of individual evaporators. These systems have the technical advantage that they take advantage of the heat of condensation of the steam generated in each individual evaporator, so that energy savings are proportional to the number of evaporators. As an example, in a three evaporator system, the energy expenditure can be reduced to less than 40% that would correspond to a single evaporator. These equipments have a wide use in the state of the prior art, so that extensive explanations will not be entered and emphasis will be placed on those peculiarities thereof that are not usual. However, the multi-effect evaporators described in the state of the art are not suitable for drying blood, or in the best case they are used to concentrate it to a certain level, for example 25% wet solids , and then send the blood to a terminator device.

The finalizing devices are responsible for removing the moisture that could not be eliminated in the previous equipment, up to the desired degree of humidity, which allows its commercialization and conservation. This degree of humidity is typically 8-10%. A typical example of a finishing device is spray or spray dryers. In them, the previously preconcentrated blood is sprayed by an atomization mechanism and is passed through a stream of hot air at about 170 ° C. These teams have serious drawbacks. On the one hand, since the water vapor eliminated by the dry product is not reused, it is more expensive than the multi-effect evaporators mentioned in the previous paragraph. On the other hand, the remarkable increase in temperature, although the contact time between blood and air is very short, contributes to increase protein denaturation.

The main reason why conventional multi-effect evaporators are not suitable for performing the entire blood drying process, is that they work poorly with moderately viscous or very viscous fluids. If they are natural circulation evaporators, they can present operating problems even at low viscosities. The inclusion of forced circulation pumps allows working with higher viscosities, but which are still lower than those reached by the blood during its drying process. On the other hand, blood has a tendency to form scale on the exchange surfaces, which significantly decrease the heat transfer coefficient.

Another relevant phenomenon is that blood is a biologically active fluid, with the presence of animal cells and an important biochemical activity. This characteristic establishes a crucial difference between blood and commonly used industrial fluids. Part of this activity consists in the formation of clots of blood components, largely due to the action of fibrin. These properties must be taken into account in the evaporator system.

DESCRIPTION OF THE INVENTION

Therefore, there is a need for new blood processing systems and / or derivatives that solve at least some of the problems mentioned. It is an objective of the present invention to satisfy said need.

The present invention relates to a system that allows to obtain a dried product from liquid blood and / or derivatives at low temperature and with a moderate energy cost. The liquid blood to be treated is that obtained preferably from the meat industry, such as a slaughterhouse.

For the present invention, the term "blood" also includes products derived therefrom that are applicable.

As already explained, blood, as a fluid of biological origin, has a biochemical activity that gives it fundamental differences with respect to the majority of fluids that are treated with heat exchangers in the state of the art. This invention was born with the motivation of having all these differences in mind, to provide an effective solution to the blood drying process.

The main peculiarity of the blood is the coagulation phenomenon. While it is in circulation in living beings, it is normally inhibited, but once spilled outside, coagulation occurs, in a time that is usually on the order of several minutes. Coagulated blood is difficult to pump, it flows with difficulty and dirties the heat exchange surfaces, so that drying treatments become very difficult. The biochemical mechanism that causes coagulation is as follows. The blood has a protein, fibrinogen, which through the enzyme thrombin is transformed into fibrin, another protein, fibrillar and non-globular, with the ability to polymerize and thus form large three-dimensional networks. These networks act as a glue, and easily trap large amounts of blood cells, thus forming a clot.

There are several possibilities to avoid or limit coagulation. The addition of anticoagulant salts is a widespread one, but which has the disadvantage of increasing the boiling temperature, which damages the evaporators and is therefore ruled out in this invention. An alternative is to provide the blood with movement, as coagulation is delayed. Another possibility is to pass through the blood through certain agitator elements, on which the fibrin networks stick together. In doing so, they separate from the rest of the fluid and stop acting on their cells and other suspended components.

In the present invention, the adverse effects of fibrin are counteracted by the following four actions:

1) Provide blood movement. 2) Exercise tangential tensions.

3) Facilitate the accumulation of fibrin on a mobile surface.

4) Scratched heat exchange surfaces, to remove possible incrustations of fibrin or clots.

The concept of "tangential tensions" is interpreted in this document from the point of view of continuous media mechanics, as that situation in which the Cauchy tension tensor has important components outside the diagonal.

As for the third point, said mobile surface does not perform any thermal exchange, so there is no problem in the accumulation of fibrin on it.

In order to provide an effective solution to the situations described here, thermal exchange plates in vertical position are arranged as a preferred option, each separated from the adjacent one a distance of the order of several centimeters. The vertical orientation prevents the decantation of particles or clots on the exchange surfaces, and the short separation distance increases the exchange surface / volume ratio of the exchanger. An additional measure includes the inclusion of agitators in the chambers covered by blood. So that between two adjacent vertical plates, it is encased to the Less an agitator. This type of configuration and geometry, is of special interest in the treatment of blood, since it produces a turbulent flow of great magnitude, even with stirrers moving at low revolutions per minute, for example of the order of 20 rpm That is, it is minimized energy expenditure while giving the blood a movement, through the turbulence that runs through your breast, which limits clotting.

Another relevant measure, which this invention makes use of, is the use of agitators with an angle of attack of 90 ° (later described, called as a second plurality) and which pass at a very small distance from the heat exchange surfaces, of the order of several millimeters. When moving, they displace the blood and force a part of it to go through this little separation between agitator and thermal plate. During this transit the shear stresses increase greatly, because in that spatial scale the viscous stresses are very relevant. The shear stresses generated are an additional measure that the present invention introduces to limit the formation of newly created fibrin networks, and destabilize those already formed. Finally, this type of agitator catches on its surface those polymerized fibrin networks whose formation could not be avoided by turbulence or by shear stress.

The production system of a dried product from liquid blood or derivatives object of the present invention is characterized in that it comprises: a. multi-effect evaporator system, characterized in that heat exchangers include stirring mechanisms; b. a heat pump that provides power to the evaporator system; and c. a condenser

The system object of the present invention is characterized in that the heat pump absorbs heat from an industrial effluent, which is at a temperature in the range 30-80 ° C.

In a preferred embodiment the heat pump comprises a first heat exchanger connected in series to a second heat exchanger. In the heat pump, a fluid circulates in a closed circuit, which is subjected to various pressure changes, by the action of a compressor; by way of non-limiting example, this fluid may be the refrigerant R-134a, which in the first heat exchanger operates at a pressure in the range 1 - 5 bar, while in the second heat exchanger it operates at a pressure in the range 15 - 30 bar.

The multi-effect evaporator system comprises a. two or more multi-effect evaporators characterized in that they reduce blood moisture to a value less than 25% on a dry basis; b. plate heat exchangers; C. a first plurality of stirring mechanisms characterized in that they scratch the heat exchange surface eliminating scale; and d. a second plurality of agitator mechanisms characterized in that they exert a removal that limits the negative effects of fibrin.

In the present invention the term "steam" refers to water vapor with the possibility of incorporating other volatile substances or non-condensable gases, such as C0 ₂ , atmospheric air, etc., which are released by the blood itself, or accidentally introduced by leaks from outside. In a preferred embodiment the multi-effect evaporator system is located on the same vertical.

In a preferred embodiment the multi-effect evaporator system is comprised of two evaporators; In an even more preferred embodiment, the multi-effect evaporator system is comprised of three evaporators. In a particular embodiment of the invention the first plurality of stirring mechanisms sweeps the surfaces of the plate heat exchangers, and comprises rotating blades that press on them by the action of a spring or equivalent mechanism. In an alternative embodiment the first plurality of stirring mechanisms comprises brushes. The action of this first plurality of agitating mechanisms guarantees the removal of those particles that could adhere to the exchange surface, such as red blood cells, fibrin, albumin, or any type of clot. The blades, in addition, mechanically break the fluid boundary layer in contact with the surface, thereby significantly increasing the heat transfer coefficient. In a preferred embodiment of the invention, the heat exchange surface of the heat exchangers comprises plates located vertically. In a configuration Preferably, the exchangers have two chambers: a first chamber of the heating fluid and a second chamber of the product to be dried. The fluid that provides heat for drying circulates in the first chamber. Between each two adjacent plates, there is a sub-chamber belonging to one of both cameras mentioned. As an example, considering an exchanger with 10 plates, correspondingly numbered 1, 2, 3, 10, between pairs 1-2, 3-4, 5-6, 7-8 and 9-10 circulates the blood to be dried, and between the complementary pairs: 2-3, 4-5, 6-7 and 8-9 circulates the heating fluid. These types of configurations and their operation are known in the state of the art, and no further clarification is necessary. The separation contemplated between each pair of adjacent plates is of the order of several centimeters.

In the present invention, the term slender refers to a rectangular geometric configuration in which two sides are several orders of magnitude greater than the other two.

The second plurality of stirring mechanisms has a slender rectangular section that maximizes the accumulation of fibrin on its surface, separating it from the rest of the fluid. The last evaporator of the evaporator system is characterized in that it comprises a third plurality of stirring mechanisms comprising one or more blades that displace blood or derivatives in the heat exchanger. In a preferred configuration, the blades of this third plurality of agitator mechanisms have a thicker section than those of the first and second plurality of agitators, in order to withstand the mechanical stresses, which are expected to be greater. In addition, a concave section is especially advantageous, since it facilitates a greater accumulation of product on its surface, and therefore a more effective removal thereof. A concave profile, by retaining a greater quantity of product, produces that each revolution of the axis moves more quantity of the same and therefore reduces the homogenization time.

In the present invention, the term "homogenization time" refers to the time it takes for an agitator mechanism to remove the product until the particles with a higher degree of moisture have dispersed in a homogeneous manner between the particles with a lower degree of humidity, or vice versa. In summary, three types of agitators have been contemplated so far. A first plurality exerts a scratching effect on the exchange surfaces, A second plurality generates a removal that limits the adverse effects of the fibrin, and a third plurality is in the last evaporator and homogenizes the product. The outlet steam generated by the evaporator system is collected by a condenser that is fed with water, which comes from the water supply network to an industry and is at the usual network temperature, in the range 7 - 20 ° C. In one aspect of the present invention the second plurality of stirring mechanisms generates a movement in the fluid and also promotes adhesion on its surface of fibrin networks that cannot be destabilized with said movement. When the process is finished, for example at the end of each working day, the evaporator is opened and the fibrin is manually removed. The three pluralities of agitators are located in the confined space between two consecutive exchange plates.

The scrapers of the first plurality of stirring mechanisms, in their shape in the form of blades, have a very sharp angle edge, designed to offer a high cutting capacity, and that exerts the effect of scratching. The angle of attack of scrapers moving with respect to blood, thus defined in analogy with the angle of attack of the wing of an aircraft, is also acute. As a clarification, an angle of attack of 0 ^{o would} mean that the agitator is placed parallel to the plate on which it acts, and an angle of 90 ° would mean that it is located perpendicular to the plate. It is contemplated that this angle is less than 30 °. On the other hand, scrapers are subjected to the action of a spring or similar mechanism that presses them against the plates. This implies that they will have a thickness greater than that corresponding to the second plurality of agitators, because they have to withstand higher mechanical stresses.

The mobile elements of the second plurality of agitator mechanisms, designed for the retention of fibrin and the limitation of coagulation, move with an angle of attack of 90 ° or close to said value. This angle facilitates the formation and maintenance on the agitator of the fibrin clusters that do not destabilize with the turbulence or tangential tension of the fluid. If the angle were smaller, the agitator would cut the fluid more easily and the accumulations would take longer to form on its surface, and once formed they would tend to detach more easily and quickly, which could induce them to stick on more stable surfaces, such as heat exchange plates, which would be very negative. On the other hand, if fibrin clusters break off the agitator and remain in suspension, which would be more likely with an acute angle of attack, they could also damage the system, as fibrin clusters worsen the rheological properties of the fluid and complicate the its drive through possible pumps. Unlike scrapers, agitators of the second plurality do not exert contact on the exchange plates, but extend in a preferred manner up to a short distance thereof. A short distance can be interpreted in the order of several millimeters. The section of the stirrers, obtained through a cross-sectional plane, is preferably rectangular.

The third plurality of stirring mechanisms has the function of displacing the treated product when it has no liquid consistency, in a manner similar to that of a shovel by displacing a granulated product. To facilitate this task, the agitators are positioned at an angle of attack of 90 ° or close, and it is contemplated that its shape is concave, to enhance the ability to accumulate product and raise it in the upward paths of the agitator. The thickness of this third plurality is expected to be greater than that of the other two, to withstand the mechanical stresses involved.

In a preferred embodiment the first and second plurality of agitators, formed by scraper elements and elements to limit the negative effects of the fibrin, respectively, describe a circular motion, as they are fixed to a rotary axis that crosses the length of the heat exchanger, driven by a motor located outside the exchanger.

It is worth mentioning the special advantage of having vertical plate heat exchangers. They establish an improvement of great magnitude with respect to traditional blood drying equipment, such as the digester type, traditional forced circulation evaporators, etc. In digesters, the exchange surface is only an outer jacket with a cylindrical shape. By dividing and sharing the volume of the exchanger by means of a succession of exchange plates, a much larger exchange surface is obtained for the same volume of exchanger. On the other hand, being the agitators encased between two adjacent plates, their movement generates a much greater turbulence than that obtained in digesters or forced circulation evaporators. As an example, if the separation between adjacent plates is 100 mm, the width of the stirrers can be 95 mm. It is observed that they move very close to the edges of both plates. In an equivalent way to the effect of the baffle plates in tanks with agitation, this boxing of the agitators greatly increases the turbulence, which in turn improves thermal exchange, limits the formation of clots and reduces the formation of scale.

An undesirable phenomenon present in the devices of the state of the art, and which the present invention counteracts, is the increase in coagulation speed with the temperature. Although the working temperatures of the multi-effect evaporators can be very low (temperatures below 55 ° C are contemplated in this invention), they always induce a higher coagulation than at room or refrigerated temperature. This reason has meant that in the state of the art treatments aimed at removing fibrin from the blood are carried out at a stage prior to the water removal process, usually at low temperatures (for example with cooling to less than 8 ° C) . However, the arrangement of agitators encased between vertical plates generates a greater turbulence than usual in devices of the prior art, counteracting the increase in coagulation and allowing the work with whole blood that has not been previously defibrinated. This advantage saves time and the need for a stirred tank with cooling equipment in many cases.

On the other hand, defibrination techniques prior to the drying process do not prevent subsequent coagulation. While this process removes most of the fibrin and coagulation tendency is greatly reduced, it is never completely eliminated and clots will occur in the drying process. The present invention provides that the blood is under the action of scrapers and removers in all evaporators in which liquid is found, whereby the removal of fibrin (and blockage of coagulation) is continuous throughout the entire process of dried

The last evaporator, the one in which the blood leaves the system with the desired degree of humidity, has, in a preferred but not limiting manner, displacement blades and not agitators for the retention of fibrin. This is because in the last evaporator the blood has lost its liquid consistency, and it cannot move like a fluid. The blades have surfaces of similar shape and dimensions to those of the stirrers, but with a greater mechanical resistance, in such a way that they are capable of supporting and displacing the weight of the accumulated blood between each two adjacent plates.

BRIEF DESCRIPTION OF THE FIGURES

The modalities detailed in the figures are illustrated by way of example and not by way of limitation:

Figure 1 shows a flow chart of the system object of the present invention. Figure 2 shows an enlarged detail of an evaporator. Figure 3 shows a particular embodiment of an evaporator.

Figure 4 shows an enlarged detail of the evaporator according to Figure 2.

Figure 5 shows a perspective of an evaporator according to Figures 2 and 3.

Figure 6 shows a sectioned perspective view of two exchange plates Figure 7 shows a representation of the first plurality of agitators present in the first and second evaporators.

Figure 8 shows a representation of the second plurality of agitators present in the first and second evaporators.

Figure 9 shows the third plurality of agitators. DETAILED DESCRIPTION OF THE INVENTION

A flow chart of a particular embodiment of the system object of the present invention is shown in Figure 1 - As can be seen in Figure 1, in this particular embodiment three evaporators (1, 2 and 3) are arranged in series, forming as a whole a multi-effect evaporator system that operates under vacuum. Each individual evaporator consists of two chambers: an evaporation chamber (5a, 5b and 5c) and a condensing chamber (4a, 4b and 4c). In this document, when reference is made to an evaporation chamber, but without specifying to which evaporator (1, 2 and 3) it belongs, it will be indicated by (5), and will proceed in the same way with the evaporation chambers (4 ). In the evaporation chamber of the first evaporator (5a), the product to be dried is always found. In the first evaporator (1), the R-134a refrigerant circulates through the condensation chamber (4a), which has qualities that make it suitable for use in the food industry. In the condensation chamber (4b) of the second evaporator (2), the steam generated in the evaporation chamber (5a) of the first evaporator (1) circulates. And in the condensation chamber (4c) of the third evaporator (3), the steam generated in the evaporation chamber (5b) of the second evaporator (2) circulates. The inlet and outlet of fluid to the condensation chambers (4a, 4b and 4c) of each evaporator (1, 2 and 3) is done through manifolds (6a, 6b and 6c).

The steam that circulates through the condensation chamber (4b) of the second evaporator (2), yields its latent heat of condensation to the blood of the evaporation chamber (5b) of that same evaporator (2), which is possible due to that both chambers (4b and 5b) are at different pressures. Consequently, the steam condensation temperature It is higher than the boiling temperature of the blood, which allows heat transfer. The liquid obtained through the condensation of the steam in the second evaporator (2) is purged out of the system by means of a centrifugal pump (10). Everything described in this paragraph also applies to the third evaporator (3).

The steam leaving the third evaporator (3) is conducted to a condenser (11), which comprises a heat exchanger (1 1a) of the casing and tube type. On the side of the housing circulates the steam to condense, and inside the tubes circulates water from the supply network to the meat industry, at a temperature lower than that of the steam. This water comes at a usual temperature between 7 and 20 ° C, depending on the place and time of the year, and is used in large quantities by slaughterhouses, for tasks such as cleaning, sterilization, boiler feed, etc. At the outlet of the exchanger (1 1a), the mains water is at a higher temperature than the inlet. Taking into account that meat industries or slaughterhouses need to heat a large part of the network water they consume, this exchanger (1 1a) represents energy savings. As an example, it is typical that a slaughterhouse needs to heat 60% of the mains water it consumes at temperatures above 62 ° C, to be used as cleaning water. Mains water is driven through the exchanger (1 1a) by means of a centrifugal pump (1 1 b).

Inside the casing of the heat exchanger (11a) of the condenser (11), and externally to the tubes, condenses the steam from the third evaporator (3), yielding its heat of condensation to the mains water. The liquid formed is expelled to the outside of the exchanger (1 1a) by means of a centrifugal pump (1 1c), conveniently located in the lower area of the exchanger (11 a), to facilitate its drainage and priming of the duct that sucks the pump ( 11 c). That part of the steam that has not been able to condense, is expelled to the outside of the condenser (1 1) by means of a vacuum pump (11 d), conveniently located in the upper area of the exchanger (11 a), to prevent the entry of liquids . The operating vacuum in the evaporation chamber (5c) of the third evaporator (3) is maintained both by the condensation of the steam in the condenser (1 1) and by the action of the vacuum pump (11 d).

The raw blood is extracted from freshly slaughtered animals by a hygienic mechanism consisting of a hollow blade knife connected to a suction tube. Next, the blood is introduced directly into the first evaporator (1), through of an inlet duct (7a). In this evaporator (1) the blood loses moisture and then leaves the evaporator through an outlet duct (8a).

The inlet ducts (7a, 7b and 7c) have been placed in a higher position than the outlet ducts (8a, 8b and 8c), and the latter are at the bottom of the evaporator (1, 2 and 3), to facilitate the drainage of blood.

The blood that leaves the first evaporator (1) is driven to the inlet duct (7b) of the second evaporator (2) with the help of a peristaltic pump (9a). Once the blood has lost a certain degree of moisture in the second evaporator (2), it leaves it through its outlet duct (8b) and is then displaced, with the help of a peristatic pump (9b), to the duct inlet (7c) of the third and last evaporator (3), where it will reach the desired degree of humidity for marketing as blood meal. The dried product is expelled from the evaporator system, through the outlet duct (8c) of said third evaporator (3).

In an alternative embodiment, the three evaporators (1, 2 and 3) are in the same vertical, so that the blood moves from one evaporator to the next due to gravity.

The energy required for the evaporation of the blood is provided by a heat pump (12), which comprises a shell and tube heat exchanger (12a). A residual effluent from the meat industry circulates inside the housing and externally to the tubes, driven by a centrifugal pump (12b). This effluent includes the industrial cleaning waters, pig scalding waters, animal urine, etc. The cleaning waters, it is common that they are used with a temperature of around 65 ° C, with which they usually go to the drain, once used and assuming that there is no heat pump, with a slightly lower temperature, for example 55 ° C. On the other hand, slaughterhouses using the technique of scalding pigs use water at a temperature between 60 and 85 ° C, which once used slightly cools and becomes a contaminating residue, which has been of treating in a purification station. Whether from one source or another, residual fluents have a temperature low enough to make their energy use very difficult or unprofitable by common technical means. However, the heat pump (12) effectively absorbs the thermal energy of the residual effluents and delivers it to the refrigerant R-134a, which circulates inside the tubes of the exchanger (12a). Being absorbing energy from a residual effluent, which is produced inevitably and whose destination is the drain or a purifier, there is a significant reduction in energy costs in the process of drying the blood. The heat pump can absorb energy from the residual effluent as long as it has a temperature above 30 ° C.

In this particular embodiment, the residual effluent enters the exchanger (12a) at a preferred temperature of 40 ° C and leaves it at a preferred temperature of 25 ° C. This heat that has yielded is absorbed by the R-134a fluid, which evaporates inside the exchanger tubes (12a) at a temperature of 10 ° C and a preferred pressure of 4.25 bar. This fluid is conducted to the compressor (12c), which raises its preferred pressure from 19.5 bar, corresponding to a condensation temperature around a preferred temperature of 65 ° C. Once it enters the condensing chamber (4a) of the first evaporator (1), it condenses and delivers the heat of condensation to the raw blood entering the evaporation chamber (5a) of that same evaporator (1). Once condensed, it crosses a rolling valve (12d), which reduces its pressure, and returns in a liquid state to the exchanger (12a) to be evaporated again, and thus describing a closed circuit. A schematic drawing of an evaporator is shown in Figure 2, to illustrate the nomenclature used herein. The measures and proportions are exaggerated in order to increase clarity. A housing (13) can be seen, inside which a total of six heat exchange plates (14a, 14b, 14c, 14d, 14e and 14f) are housed. In this particular embodiment an evaporation chamber (5) is shown, through which blood circulates, and a condensation chamber (4), through which steam circulates. The paths of blood and steam are indicated representatively by means of sinuous arrows; for the steam the line thickness is thin, and for the thick blood. The separation between both chambers (4 and 5) is watertight, so that at no time contact between the two fluids occurs. The condensation chamber (4) comprises in this particular embodiment a total of three subchambers (20a, 20b and 20c), which are all connected, via pipes (6y), to two manifolds (6), so that they form a single volume, said condensation chamber (4). The evaporation chamber (5) comprises four subchambers (19a, 19b, 19c and 19d), which are also all in communication, also forming a single volume, said evaporation chamber (5). Inside each of the subchambers (19a, 19b 19c and 19d) of the evaporation chamber (5), an agitator (23) is housed, driven by a shaft (16).

It is appreciated that between each two adjacent plates, a subchamber is housed. Thus, for example, between the plates (14a) and (14b) is the sub chamber (20a), belonging to the condensation chamber (4). And between the plates (14b) and (14c) is the sub chamber (19b), belonging to the evaporation chamber (5). Note that at each of the two ends of the evaporator is a sub-chamber (19a and 19d), which as an exception is not located between two adjacent plates (14a, 14b, 14c, 14d, 14e and 14f), but between plate and housing (13).

A particular embodiment of an evaporator is shown in Figure 3, and it can be any of the three (1, 2 or 3). The evaporator comprises an outer casing (13), which houses inside the heat exchange plates (14) and stirrers (23), which describe a rotational movement by means of a fastener to an axis (16), said axis being driven by a motor (17), outside the housing (13). The shaft is supported inside the evaporator by means of respective supports (18), which hold it while promoting its rotation. For this, the supports (18) are constituted as sliding contact bearings, without the need for lubrication.

The housing (13) has in its upper part two mouths of man (21), with the purpose of allowing access to its interior for cleaning, inspection, repair, etc. They are especially advantageous for cleaning and manual removal of fibrin clusters, after each work day. In the central part is a gravimetric settling duct (22), which helps to purify the steam obtained from the boiling of the blood. More specifically, its diameter is selected such that the rate of ascent of the gases is slow enough so that those liquid particles in suspension do not follow the gas its upward path along the conduit (22), but rather precipitate by gravity. In the upper area of said duct (22), there is a steam outlet pipe (not shown in the figure), to be conducted to the next evaporator (1, 2 or 3), or if necessary the condenser ( eleven). The blood is introduced at a point (not shown in the figure) of the upper evaporator zone, falls by gravity and goes on to occupy the volume of each of the subchambers (19) of the evaporation chamber (5). These subchambers (19) are run by agitators (23), attached to the shaft (16) and that develop a rotational movement. In this way, the blood is at all times under agitation mechanics. If the evaporator represented is the first (1) or the second (2), the agitators (23) will be of two different types, those belonging to the first and second plurality of agitators, represented in Figures 5 and 6. Preferably , in each of the subchambers (19) are both types of agitators

The sub-chambers (20) of the condensation chamber (4) must allow them to be traversed by the rotating shaft (16), and at the same time maintain the tightness between both chambers (4 and 5). For this, each pair of adjacent plates (14) delimiting a sub-chamber (20), have a circular perforation in its center, traversible by the axis (16), and a concentric cylindrical part (24) with both perforations, but of greater diameter and welded to both plates (14). This ensures the mobility of the shaft (16) and the tightness. To delimit the condensation chamber (4) and make it sealed, there are enclosures (25) welded around the perimeter of each pair of adjacent plates (14) enclosing a sub chamber (20). The enclosures (25) adapt to the geometry of the joining plates; if, for example, the plates to be joined are circular, the enclosures will have a circular crown shaped section. The solutions described in this paragraph and in the previous one are common in the state of the art, and further explanations are not considered necessary.

In the lower part of the evaporator represented, the outlet duct (8) of the blood is placed. Through it the blood is evacuated to the next evaporator (2 or 3), or to the outside of the system, if applicable, if it is the third evaporator (3).

In Figure 4, a detail of Figure 2 is shown. A total of six vertical heat exchange plates (14) are observed. Between each of them adjoining, a subchamber is established. Sub-chambers (19) of the evaporation chamber (5) and sub-chambers (20) of the condensation chamber (4) are appreciated, with their corresponding enclosures (25) that guarantee the tightness between both chambers (4 and 5), which are They have alternately. In the first (19), stirrers (23) are placed, which in this figure are not specified as belonging to any of the three pluralities (23a, 23b or 23c). The agitators (23) are attached to the shaft (16), which gives them the rotation movement. The rotary axis (16) passes through one of its supports (18) and crosses, through its central part, the six plates (14) and the three subchambers (20) of the condensation chamber (4) as shown in this figure. To ensure tightness, cylindrical pieces (24), concentric with the perforations of the plates (14), are welded into the corresponding pairs of plates (14). The figure shows a total of three of these pieces (24). As can be seen, the shaft (16) is immersed in the evaporation chamber

(5), and therefore it is bathed by the product to be dried.

Figure 5 shows a perspective image of an evaporator according to Figures 2 and 3. The housing (13) is partially sectioned, to make its interior visible, as well as a part of the exchange plates (14 ). The motor (17), the shaft (16) that it drives, and agitators (23) attached to it, without defining to which plurality they belong (23a, 23b or 23c) are appreciated. The enclosures are equally visible (25). To connect all the subchambers (20) of the condensation chamber (4), and thus constitute a single volume, all of them are connected to a collector

(6), through pipes (6a). In the figure, a pipe (6a) is placed for each subchamber (20), where the pipes (6a) enter the interior of the subchambers (20), crossing their enclosures (25). In this case, the manifold (6) is an outlet, since it is in a lower area, and the condensed fluid (R-134a or steam, if applicable), accumulates on it. By a criterion of simplicity, in this figure the mouths of man (21) and the conduit of decantation (22) have been omitted.

In Figure 6, a sectioned perspective view of two exchange plates (14) is shown, the outer enclosures (25) and the cylindrical part (24) being visible between both plates (14). The interior of the cylindrical part (24) is crossed by the shaft that moves the agitators (not shown in this figure). A subchamber (19) of the evaporation chamber and a subchamber (20) of the condensation chamber are indicated. This figure has the utility of showing in perspective the mentioned elements, to help its better understanding, but in no case it constitutes a limiting example of the scope of the invention.

In Figure 7, a representation of the first plurality of agitators (23a), present in the first (1) and second (2) evaporator is shown. It shows two adjacent exchange plates (14), among which there is a sub-chamber (19) belonging to the evaporation chamber (5). Therefore, it contains blood to dry. The shaft (16) crosses the subchamber (19) and describes a rotation movement, as indicated by the figure. The agitator (23a) comprises a scraper blade (15), which presses against one of the plates (14) by means of the action of a metal sheet (26). Said sheet (26), at rest has a straight conformation, but as seen in the figure, it is installed by forcing a curvature. In this way, the sheet (26), by virtue of its tendency to recover its initial straight conformation, exerts a mechanical tension that presses the blade (15) against the wall of the plate (14). The angle of attack with which the blade (15) cuts to the blood is acute and less than 30 °. This configuration favors its ability to descale plate deposits (14), and generates a mechanical destabilization of the fluid boundary layer contact with the plate (14), so that the thermal transfer coefficient increases considerably.

For the limitation of coagulation, two phenomena are sought: an important turbulence within the fluid, and the ability to attract and accumulate fibrin on certain surfaces, so that it separates from the rest of the fluid, thus limiting its ability to form clots. . In this sense, the blades do not generate a turbulence within the fluid that is of the appropriate magnitude, although they do generate it in the boundary layer. On the other hand, its angle of attack hinders the adhesion and subsequent consolidation of fibrin on its surface. For these reasons, it is essential to separate the functions of descaling and breaking the boundary layer, from the limitation of coagulation, which is reserved in particular for the second plurality of agitators (23b).

It should be noted that the first plurality of agitators (23a) is that which has the conformation that contributes most to the increase in the heat transfer coefficient, by mechanically breaking the boundary layer of blood.

A representation of the second plurality of agitators (23b), present in the first (1) and second (2) evaporator, is shown in Figure 8, as is the first plurality of agitators (23a). Two adjacent thermal plates (14) are observed, among which a sub chamber (19) of the evaporation chamber (5) is housed. That is, it contains blood inside. The rotating shaft (16) and the stirrer (23b) are represented. This has a conformation similar to that of a shovel or paddle, with a slender rectangular section, and approaches the walls of the plates (14) until it is at a preferred distance of 3 mm from each of them. The angle of attack with which it passes through the fluid is 90 ° or close. This arrangement generates a very intense turbulence within the fluid, which favors non-coagulation, and the angle of attack enhances the formation and retention on its surface of those fibrin networks that could not be avoided by agitation.

It is observed that through the said separation between the plates (14) and the stirrer (23b), of 3mm, a certain volume of blood is forced to circulate. The passage through this narrow space generates high shear stresses that destabilize the formation of fibrin networks.

Another relevant phenomenon here is that the closer both plates (14) are, the greater the effect of the shear stress on the fibrin. This is because when approaching the plates (14), the same surface swept by the stirrers (23b) is maintained, but the volume of blood between both plates (14) is smaller, so that the ratio: (surface to be traversed ) / (blood volume) gets bigger. As a consequence, the closer the plates, the less time it takes for the entire volume of blood between plates (14) to pass through said separation between agitator (23b) and plate (4), which in this embodiment is 3 mm.

In Figure 9, the third plurality of agitators (23c) is shown. In this embodiment of the invention, they are the only agitators present in the third and last evaporator (3), although this characteristic is not limited to the scope of the invention. The three types of stirrers (23a, 23b and 23c) could be available in any of the evaporators (1, 2 or 3), although it is not a preferred configuration. Two adjacent plates (14) are appreciated, among which a sub-chamber (19) belonging to the evaporation chamber (5), bathed in blood, is housed. The rotary axis (16) and the stirrers (23c) are also observed. These have concave shaped shovels, which enhances the ability to drag product. Their thickness is designed to provide adequate mechanical resistance to displace the weight of the blood when it has ceased to be a fluid. This differentiation in the design is fundamental, since an agitator that was designed to remove fluid blood, if used to remove blood that has stopped flowing, would be subjected to very important mechanical stresses that would greatly limit its useful life.

Claims

1. System for producing a dried product from liquid blood or derivatives characterized in that it comprises: a. multi-effect evaporator system, characterized in that heat exchangers include stirring mechanisms; b. a heat pump that provides power to the evaporator system; and c. a condenser

2. The system according to claim 1, characterized in that the heat pump absorbs heat from an industrial effluent.

3. The system according to claims 1 and 2, characterized in that the heat pump comprises a first heat exchanger connected in series to a second heat exchanger.

4. The system according to claim 3, characterized in that the first heat exchanger operates at a pressure in the range 1-5 bar.

5. The system according to claim 3, characterized in that the second heat exchanger operates at a pressure in the range 15-30 bar

6. The system according to claim 2, characterized in that the industrial effluent is at a temperature in the range 30 ° C - 80 ° C.

7. The system according to claim 1, characterized in that the multi-effect evaporator system comprises a. two or more multi-effect evaporators characterized in that they reduce blood moisture to a value less than 25% on a dry basis; b. plate heat exchangers; C. a first plurality of stirring mechanisms characterized in that they scratch the heat exchange surface eliminating scale; Y d. a second plurality of agitator mechanisms characterized in that they exert a removal that limits the negative effects of fibrin and / or blood clotting.

The system according to claim 7, characterized in that the first plurality of agitators has an acute angle of attack, and the second plurality of agitators has an angle of attack of 90 °

9. The system according to claim 7, characterized in that the second plurality of agitators has an angle of attack of 90 ° and passes at a distance of 3 millimeters from the heat exchange plates.

10. The system according to claim 7, characterized in that the multi-effect evaporator system is located on the same vertical.

11. The system according to claim 7, characterized in that the second plurality of stirring mechanisms has a slender rectangular section.

12. The system according to claim 7, characterized in that the last evaporator of the evaporator system is characterized in that it comprises a third plurality of stirring mechanisms.

13. The system according to claim 12, characterized in that the third plurality of stirring mechanisms comprises one or more blades that displace blood or derivatives in the heat exchanger.

14. The system according to claim 1, characterized in that the steam generated by the evaporator system is collected by a condenser that is fed with water.

15. The system according to claim 1, characterized in that the water comes from the water supply network to an industry, at the usual network temperature.